Generic apparatuses are used, in particular, for medical purposes in the field of computer radiography (CR). X-ray exposures are recorded in a phosphor layer, X-radiation which passes through an object, for example a patient, being stored as a latent image in the phosphor layer. To read out the latent image the phosphor layer is irradiated with stimulation light, the phosphor layer emitting emission light corresponding to the latent image, which emission light is captured by an optical detector and converted into electrical signals. The electrical signals may be further processed as required and displayed on a monitor, or outputted on a suitable output device, e.g., a printer.
Known from the prior art are apparatuses in which the stimulation light emitted by a radiation device impinges at a specific angle on the phosphor layer, in a linear zone of which it stimulates emission light which is captured at a specific angle by a detector. In order to capture the entire latent image stored in the phosphor layer the irradiation device and the detection device are moved relative to the phosphor layer, whereby the linear zones of the phosphor layer are successively stimulated and read out.
In the apparatuses known from the prior art, depending on the selection of the angles at which the stimulation light impinges on the phosphor layer and at which the emission light emitted by the phosphor layer is detected, losses in the intensity of the emission light to be detected, and/or in the definition of the linear zone of the phosphor layer stimulated, occur in certain applications. In these cases the high quality of the image information read out, which is required for reliable medical diagnosis, cannot be guaranteed.